In a data processing system, or in a component such as a disk control unit, customer data is frequently moved between storage elements, such as external storage drives, internal processor memory, conventional volatile RAM, non-volatile memory, etc. A list is typically maintained of entries which are associated with the data. Entries may include memory addresses, pointers or other means of identifying the data which is being moved. Entry lists conventionally have been built and maintained through instructions executed by a controller processor. However, building and maintaining a list consumes valuable processor resources. Moreover, spurious writes to the list may be undetected or an entry in the list may be corrupted, possibly leading to data being lost or unavailable and placing the integrity of the list in question.
Consequently, a need remains for a means of maintaining an entry list which is efficient and relieves the controller processor from at least some of its former responsibilities. There remains a further need to maintain an entry list while enhancing the ability to detect errors.